/* Copyright (c) 2010, 2024, Oracle and/or its affiliates.

 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License, version 2.0,
 as published by the Free Software Foundation.

 This program is designed to work with certain software (including
 but not limited to OpenSSL) that is licensed under separate terms,
 as designated in a particular file or component or in included license
 documentation.  The authors of MySQL hereby grant you an additional
 permission to link the program and your derivative works with the
 separately licensed software that they have either included with
 the program or referenced in the documentation.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License, version 2.0, for more details.

 You should have received a copy of the GNU General Public License
 along with this program; if not, write to the Free Software
 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA
*/

#include "CharsetMapImpl.h"

#include <string.h>

#include "my_sys.h"
#include "mysql/strings/m_ctype.h"

#define MYSQL_BINARY_CHARSET 63

/* build_map():
   Actually building the map is deferred until after my_init() etc. have
   fully initialized mysql's strings library.  They cannot be done as part
   of static initialization.
*/
void CharsetMapImpl::build_map() {
  int cs_ucs2 = 0;
  int cs_utf16 = 0;
  int cs_utf8_3 = 0;
  int cs_utf8_4 = 0;

  /* ISO 8859 Charsets */
  put("latin1", "windows-1252");  // Western Europe
  put("latin2", "ISO-8859-2");    // Central Europe
  put("greek", "ISO-8859-7");
  put("hebrew", "ISO-8859-8");
  put("latin5", "ISO-8859-9");   // Turkish
  put("latin7", "ISO-8859-13");  // Baltics

  /* IBM & Microsoft code pages */
  put("cp850", "IBM850");
  put("cp852", "IBM852");
  put("cp866", "IBM866");
  put("cp1250", "windows-1250");
  put("cp1251", "windows-1251");
  put("cp1256", "windows-1256");
  put("cp1257", "windows-1257");

  /* Asian Encodings */
  put("ujis", "EUC-JP");
  put("euckr", "EUC-KR");
  put("cp932", "windows-31j");
  put("eucjpms", "EUC_JP_Solaris");
  put("tis620", "TIS-620");

  /* Unicode */
  put("utf8mb3", "UTF-8");
  put("utf8mb4", "UTF-8");
  put("ucs2", "UTF-16");
  put("utf16", "UTF-16");
  put("utf32", "UTF-32");

  /* You could add here:
   put("filename", "UTF-8");    // No. 17: filename encoding
   ... but we're going to leave it out for now, because it should not be found
   in the database. */

  /* Others */
  put("hp8", "HP-ROMAN-8");
  put("swe7", "ISO646-SE");
  put("koi8r", "KOI8-R");  // Russian Cyrillic
  put("koi8u", "KOI8-U");  // Ukrainian Cyrillic
  put("macce", "MacCentralEurope");

  /* Build the fixed map */
  for (unsigned int i = 0; i < NDB_ARRAY_SIZE(mysql_charset_name); i++) {
    CHARSET_INFO *cs = get_charset(i, MYF(0));
    const char *mysql_name = nullptr;
    const char *mapped_name = nullptr;

    if (cs) {
      mysql_name = cs->csname;
      mapped_name = get(mysql_name);
      if (!cs_ucs2 && !strcmp(mysql_name, "ucs2")) cs_ucs2 = i;
      if (!cs_utf16 && !strcmp(mysql_name, "utf16")) cs_utf16 = i;
      if (!cs_utf8_3 && !strcmp(mysql_name, "utf8mb3")) cs_utf8_3 = i;
      if (!cs_utf8_4 && !strcmp(mysql_name, "utf8mb4")) cs_utf8_4 = i;
    }

    if (mapped_name)
      mysql_charset_name[i] = mapped_name;
    else
      mysql_charset_name[i] = mysql_name;
  }

  if (cs_utf16)
    UTF16Charset = cs_utf16;
  else if (cs_ucs2)
    UTF16Charset = cs_ucs2;
  else
    UTF16Charset = 0;

  if (cs_utf8_4)
    UTF8Charset = cs_utf8_4;
  else if (cs_utf8_3)
    UTF8Charset = cs_utf8_3;
  else
    UTF8Charset = 0;

  ready = 1;
}

const char *CharsetMapImpl::getName(int csnum) {
  if ((csnum >= (int)NDB_ARRAY_SIZE(mysql_charset_name)) || (csnum < 0)) {
    return nullptr;
  }
  return mysql_charset_name[csnum];
}

inline int CharsetMapImpl::hash(const char *name) const {
  const unsigned char *p;
  unsigned int h = 0;

  for (p = (const unsigned char *)name; *p != '\0'; p++) h = 27 * h + *p;
  return h % CHARSET_MAP_HASH_TABLE_SIZE;
}

void CharsetMapImpl::put(const char *name, const char *value) {
  unsigned int h = hash(name);
  MapTableItem *i = &map[h];
  if (i->name) {
    i = new MapTableItem;
    map[h].next = i;
    collisions++;
  }

  i->name = name;
  i->value = value;
  n_items++;
}

const char *CharsetMapImpl::get(const char *name) const {
  unsigned int h = hash(name);
  const MapTableItem *i = &map[h];
  if (i->name) {
    for (; i; i = i->next) {
      if (!strcmp(name, i->name)) return i->value;
    }
  }
  return nullptr;
}
